package org.apache.maven.project;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.maven.model.Repository;
import org.apache.maven.model.building.FileModelSource;
import org.apache.maven.model.building.ModelSource;
import org.apache.maven.model.resolution.InvalidRepositoryException;
import org.apache.maven.model.resolution.ModelResolver;
import org.apache.maven.model.resolution.UnresolvableModelException;
import org.apache.maven.repository.internal.ArtifactDescriptorUtils;
import org.eclipse.aether.RepositorySystem;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.RequestTrace;
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.artifact.DefaultArtifact;
import org.eclipse.aether.impl.RemoteRepositoryManager;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.resolution.ArtifactRequest;
import org.eclipse.aether.resolution.ArtifactResolutionException;

/**
 * A model resolver to assist building of projects. This resolver gives priority to those
 * repositories that have been declared in the POM.
 * 
 * @author Benjamin Bentmann
 */
class ProjectModelResolver implements ModelResolver {

  private final RepositorySystemSession session;

  private final RequestTrace trace;

  private final String context = "project";

  private List<RemoteRepository> repositories;

  private List<RemoteRepository> pomRepositories;

  private final List<RemoteRepository> externalRepositories;

  private final RepositorySystem resolver;

  private final RemoteRepositoryManager remoteRepositoryManager;

  private final Set<String> repositoryIds;

  private final ReactorModelPool modelPool;

  private final ProjectBuildingRequest.RepositoryMerging repositoryMerging;

  public ProjectModelResolver(RepositorySystemSession session, RequestTrace trace, RepositorySystem resolver, RemoteRepositoryManager remoteRepositoryManager, List<RemoteRepository> repositories, ProjectBuildingRequest.RepositoryMerging repositoryMerging, ReactorModelPool modelPool) {
    this.session = session;
    this.trace = trace;
    this.resolver = resolver;
    this.remoteRepositoryManager = remoteRepositoryManager;
    this.pomRepositories = new ArrayList<RemoteRepository>();
    this.externalRepositories = repositories;
    this.repositories = repositories;
    this.repositoryMerging = repositoryMerging;
    this.repositoryIds = new HashSet<String>();
    this.modelPool = modelPool;
  }

  private ProjectModelResolver(ProjectModelResolver original) {
    this.session = original.session;
    this.trace = original.trace;
    this.resolver = original.resolver;
    this.remoteRepositoryManager = original.remoteRepositoryManager;
    this.pomRepositories = original.pomRepositories;
    this.externalRepositories = original.externalRepositories;
    this.repositories = original.repositories;
    this.repositoryMerging = original.repositoryMerging;
    this.repositoryIds = new HashSet<String>(original.repositoryIds);
    this.modelPool = original.modelPool;
  }

  public void addRepository(Repository repository) throws InvalidRepositoryException {
    if (!repositoryIds.add(repository.getId())) {
      return;
    }

    List<RemoteRepository> newRepositories = Collections
        .singletonList(ArtifactDescriptorUtils.toRemoteRepository(repository));

    if (ProjectBuildingRequest.RepositoryMerging.REQUEST_DOMINANT.equals(repositoryMerging)) {
      repositories = remoteRepositoryManager.aggregateRepositories(session, repositories, newRepositories, true);
    } else {
      pomRepositories = remoteRepositoryManager.aggregateRepositories(session, pomRepositories, newRepositories, true);
      repositories = remoteRepositoryManager.aggregateRepositories(session, pomRepositories, externalRepositories,
          false);
    }
  }

  public ModelResolver newCopy() {
    return new ProjectModelResolver(this);
  }

  public ModelSource resolveModel(String groupId, String artifactId, String version) throws UnresolvableModelException {
    File pomFile = null;

    if (modelPool != null) {
      pomFile = modelPool.get(groupId, artifactId, version);
    }

    if (pomFile == null) {
      Artifact pomArtifact = new DefaultArtifact(groupId, artifactId, "", "pom", version);

      try {
        ArtifactRequest request = new ArtifactRequest(pomArtifact, repositories, context);
        request.setTrace(trace);
        pomArtifact = resolver.resolveArtifact(session, request).getArtifact();
      } catch (ArtifactResolutionException e) {
        throw new UnresolvableModelException(e.getMessage(), groupId, artifactId, version, e);
      }

      pomFile = pomArtifact.getFile();
    }

    return new FileModelSource(pomFile);
  }

}
